#include <features.h>
#include <time.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
typedef unsigned int uint32;
#define million 1000000L
long duration2ms, duration10ms, duration100ms;
double Task2ms_Raster, Task10ms_Raster, Task100ms_Raster;
timer_t firstTimerID, secondTimerID, thirdTimerID;
void TASK1(Task2ms_Raster) {
struct timespec start, stop;
int a, b, c;
uint32 StartTime, StopTime;
a=1, b=2, c=3;
if((StartTime = clock_gettime(CLOCK_REALTIME, &start)) == -1) {
perror("clock gettime");
}
a= b+c;
b = c+a;
c= a+b;
b = c+a;
c= a+b; a= b+c;
b = c+a;
c= a+b; a= b+c;
b = c+a;
c= a+b; a= b+c;
b = c+a;
c= a+b; a= b+c;
b = c+a;
c= a+b; a= b+c;
b = c+a;
c= a+b; a= b+c;
b = c+a;
c= a+b;
//我曾多次这样做过。
printf("ETAS\n");
printf("ETAS1\n");
if((StopTime = clock_gettime( CLOCK_REALTIME, &stop)) == -1) {
perror("clock gettime");
}
duration2ms = (stop.tv_sec - start.tv_sec) +
(double)(stop.tv_nsec - start.tv_nsec) /
(double)million;
printf("time difference is= %ld\n", duration2ms);
}
void TASK2(Task10ms_Raster) {
struct timespec start, stop;
if(clock_gettime( CLOCK_REALTIME, &start) == -1) {
perror("clock gettime");
}
printf("ETAS2\n");
printf("ETAS3\n");
if(clock_gettime(CLOCK_REALTIME, &stop) == -1) {
perror("clock gettime");
}
duration10ms = (stop.tv_sec - start.tv_sec) +
(double)( stop.tv_nsec - start.tv_nsec) /
(double)million;
printf("time difference is= %ld\n", duration10ms);
}
void TASK3(Task100ms_Raster) {
struct timespec start, stop;
if(clock_gettime( CLOCK_REALTIME, &start) == -1) {
perror("clock gettime");
}
printf("ETAS4\n");
printf("ETAS5\n");
if((clock_gettime(CLOCK_REALTIME, &stop)) == -1) {
perror("clock gettime");
}
duration100ms = (stop.tv_sec - start.tv_sec) +
(double)(stop.tv_nsec - start.tv_nsec) /
(double)million;
printf( "time difference is= %ld\n", duration100ms );
}
static void timerHandler(int sig, siginfo_t *si, void *uc) {
timer_t *tidp;
tidp = si->si_value.sival_ptr;
if (*tidp == firstTimerID)
TASK1(Task2ms_Raster);
else if(*tidp == secondTimerID)
TASK2(Task10ms_Raster);
else if(*tidp == thirdTimerID)
TASK3(Task100ms_Raster);
}
static int makeTimer(char *name,
timer_t *timerID,
int expireMS,
int intervalMS) {
struct sigevent te;
struct itimerspec its;
struct sigaction sa;
int sigNo = SIGRTMIN;
/* Set up signal handler. */
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = timerHandler;
sigemptyset(&sa.sa_mask);
if(sigaction(sigNo, &sa, NULL) == -1) {
perror("sigaction");
}
/* Set and enable alarm */
te.sigev_notify = SIGEV_SIGNAL;
te.sigev_signo = sigNo;
te.sigev_value.sival_ptr = timerID;
timer_create(CLOCK_REALTIME, &te, timerID);
its.it_interval.tv_sec = 0;
its.it_interval.tv_nsec = intervalMS * 1000000;
its.it_value.tv_sec = 0;
its.it_value.tv_nsec = expireMS * 1000000;
timer_settime(*timerID, 0, &its, NULL);
return 1;
}
int main(void) {
makeTimer("First Timer", &firstTimerID, 2, 2); //2ms
makeTimer("Second Timer", &secondTimerID, 10, 10); //10ms
makeTimer("Third Timer", &thirdTimerID, 100, 100); //100ms
while(1) {
sleep(100);
}
}
我创建了一个计时器，每2ms，10ms和100ms调用一次任务。任务只是打印值并计算打印值的开始时间和停止时间。当我运行上述程序时，它不显示开始时间和停止时间之间的时间差（即duration2ms，持续时间10ms和持续时间100ms）。有人可以帮助我。
答案 0 :(得分：1)
在所有情况下，时差将显示为零，因为您正在测量打印两条线所需的时间，这非常快。您不计时调用每个任务之间的时间。
如果要测量任务调用之间的时间，则需要保留时间。举个例子，我将展示一个任务：
void TASK3(Task100ms_Raster) {
static struct timespec start, stop = { .tv_sec = -1 }; // static duration!
if (stop.tv_sec < 0) {
(void) clock_gettime( CLOCK_REALTIME, &stop); // first time run
}
start = stop; // start from previous stop time
// do whatever here
(void) clock_gettime( CLOCK_REALTIME, &stop);
duration100ms = (stop.tv_sec - start.tv_sec)
+ (double)(stop.tv_nsec - start.tv_nsec)
/ (double)million;
printf( "time difference is= %ld\n", duration100ms );
}
答案 1 :(得分：0)
问题是您不能在任何地方将时间值保存在TASK *（）中。这意味着clock_gettime（）连续两次被调用，中间很少或没有时间。你应该做的是以下几点：
#include <features.h>
#include <time.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
typedef unsigned int uint32;
timer_t tmr;
struct timespec prev;
static void handle_timer(int sig, siginfo_t *si, void *uc) {
timer_t *tidp;
struct timespec current;
tidp = si->si_value.sival_ptr;
clock_gettime(CLOCK_REALTIME, ¤t);
printf("dif between calls to handle_timer: %ld\n",
current.tv_sec - prev.tv_sec);
prev = current;
}
int main(int argc, char **argv) {
struct sigevent se;
struct itimerspec its;
struct sigaction sa;
clock_gettime(CLOCK_REALTIME, &prev);
/* Set up signal handler. */
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = handle_timer;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGRTMIN, &sa, NULL) == -1)
perror("sigaction");
/* Set and enable alarm */
se.sigev_notify = SIGEV_SIGNAL;
se.sigev_signo = SIGRTMIN;
se.sigev_value.sival_ptr = &tmr;
timer_create(CLOCK_REALTIME, &se, &tmr);
its.it_interval.tv_sec = 1;
its.it_value.tv_sec = 1;
its.it_value.tv_nsec = 0;
timer_settime(&tmr, 0, &its, NULL);
while(1)
sleep(100);
return 0;
}
这里的不同之处在于我们实际上节省了调用handle_time（）的时间，然后根据节省的时间计算差异。